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CHEMISTRY. 



The accounts of the affair at hand do not state 

 whether M. Designolle's process, or some im- 

 proper modification of it, was employed there. 



Prevention of Nitroglycerine Explosions. 

 A correspondent of the London Chemical News, 

 moved by the occurrence of the frightful explo- 

 sion of "three-quarters of a ton of nitrogly- 

 cerine in Wales, involving a deplorable loss of 

 life, suggests the probable cause, and the easy 

 prevention of such calamities. He says : 



" Yet it is stated that nitroglycerine is safer 

 than gunpowder. It is certainly less liable to 

 be exploded by fire, and to disrupt the slen- 

 der link which retains its elements, subject to 

 chemical force, and set its mechanical force at 

 liberty, by concussion, needs that concussion 

 be sudden and forcible. I believe that a bottle 

 full of blasting-oil may be dashed to the ground 

 without much danger, yet a drop of it upon a 

 stone may be exploded by a blow from a ham- 

 mer. Now, what can be the possible cause of 

 such unexpected explosions as have taken 

 place ? I can see only two possible reasons : 

 first, that the oil undergoes decomposition or 

 chemical change under certain at present un- 

 known conditions, of time, temperature, shak- 

 ing, etc., which predispose it to undergo a com- 

 plete and sudden decomposition from causes or- 

 dinarily inadequate ; secondly, that the cases and 

 bottles in which it is contained being air-tight, 

 are liable, from a very trifling escape of gas 

 from the liquid, to arrive at a state of tension 

 in which the passage to a sudden break is easy. 

 But would the mere bursting open of a bottle 

 or tin case produce concussion sufficient to de- 

 termine an explosion of the oil, unless we sup- 

 pose the latter to be altered in quality ? I think 

 it would. I have known a stout glass bottle, 

 used in an ethyl experiment, to be shattered, by 

 slowly-gathered, internal pressure, into dust, 

 with a report like the firing of a pistol. In a 

 close vessel, full or very nearly full of the oil, 

 not much gas relatively to the quantity of liquid 

 need be evolved in order to induce such a de- 

 gree of pressure as might cause explosive rup- 

 ture of the vessel. If one vessel burst, the 

 concussion would certainly explode also any 

 that might be near. 



" If the true cause of these seemingly anom- 

 alous explosions is indicated above, the remedy 

 is both simple and inexpensive. Let every 

 vessel containing the oil have fitted to it a tube, 

 with a capillary bore, such as a piece of ther- 

 mometer tubing, one end of the tube entering 

 the oil, the other exposed outside. 



" If the tube were enlarged below to make 

 room for any expansion of the liquid by ele- 

 vation of temperature, none could be forced 

 out by that alone, and none could be spilt 

 through the capillary orifice of the tube by in- 

 verting the vessel. With a little management 

 in the arrangements, any overflow might be 

 made certainly indicative of the formation of 

 permanent gases, which would be a warning 

 signal. This method might also be applied ex- 

 perimentally to determine the probability or 



otherwise of the suggestion I have made as to 

 the cause that may have led to these fearful 

 explosions." 



The Aniline Colors. M.. Block publishes 

 the following recipe to produce an aniline 

 gray color : 1 kilo of aniline at 190, and 5 

 kilos of arsenic acid in a liquid form at 75, 

 are heated on the open fire in a caldron, care 

 being taken to maintain the heat at the boil- 

 ing-point, till the substance thickens and rises, 

 when the operation is terminated and the ves- 

 sel is removed. The substance obtained pre- 

 sents a blackish appearance ; it is thick and 

 insoluble in water. In order to purify the 

 product, about 20 litres of water and 1 kilo of 

 muriatic acid are taken and boiled with steam 

 for half an hour; after which the mass is fil- 

 tered. The matter which is deposited on the fil- 

 ter is collected, washed with boiling water, and 

 operated upon a third time by a small quantity 

 of carbonate of soda in solution, so as completely 

 to neutralize the acid. Finally, the collected 

 matter is dried, and gives a fine black powder. 

 The solution of this product is made by treat- 

 ing it with alcohol, with an addition of 10 per 

 cent, of sulphuric acid. Nothing now remains 

 to be done but to filter it. With this liquor 

 magnificent grays of all shades are dyed, by 

 submitting its mordant to the dyeing-bath. 

 For the dyeing and printing of this gray color, 

 the matter must first be passed through a water- 

 bath, strongly acidulated with sulphuric acid. 

 A skein of silk or wool is dyed by five drops 

 of this liquor. 



It is stated that Dr. Hofmann and Mr. Charles 

 Girard, at Berlin, have successfully obtained 

 pure aniline green, which is only distinguished 

 from the aniline violet by the elements of iodide 

 of methyl, so that the violet can be readily con- 

 verted into the green and the green into the 

 violet. 



Artificially -colored Wines. Dr. T. L. Phip- 

 son sends to the London Chemical News, of 

 November 12th, a note on varieties of coloring 

 matter, used in certain districts of France, in 

 the treatment of wines. He says that at Fismes 

 and Poitiers, and probably in other parts of 

 France, regular establishments exist where 

 coloring matter for wine is manufactured on 

 a somewhat extensive scale. The material 

 made at Fismes is obtained from elderberry, 

 both from the fruit of Sambucm niger and 8. 

 ebulus. The process is very simple : 250 to 500 

 parts of this richly-colored fruit, with 30 to 65 

 parts of alum, and 600 to 800 of water, are the 

 proportions generally employed. It has been 

 stated that beet -root juice, blackberries, 

 Brazil-wood, logwood, etc., are occasionally 

 used, but the author believes by no means so 

 frequently as the substances above named. 

 Many methods have been tried in order to de- 

 tect the presence of artificial coloring matters 

 in wines, but, it appears, with a very small 

 amount of success. (Enocyanine may be pre- 

 cipitated from the wine, and its properties, 

 studied with care, will show at once the pres- 



